Heat sink and a method of manufacturing the heat sink

ABSTRACT

A heat sink includes a base plate and a plurality of thin-sheet fins. The base plate has a plurality of recesses and protruding ribs formed between every two recesses. The protruding ribs are spaced by the respective recesses with an equal space. Each thin-sheet fin comprises a folded engaging portion and a dissipating portion connecting with the engaging portion. The engaging portion has a first extending portion and a second extending portion parallel to the first extending portion and connecting with the first extending portion. The engaging portions are inserted into the recesses of the base plate and abut against a bottom of the recesses.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat sink, and more particularly to a heat sink which is used to remove heat from an electronic component. The present invention is also related to a method of manufacturing the heat sink.

2. Description of Related Art

With the advance of integrated circuit (IC) technology, CPUs are made more and more compact and has higher operation speed than old ones. Thereby, a great deal of heat is generated. However in current trend, it is desired that the electronic devices have compact size, that is, they are smaller, and thus, it is required that the heat dissipating devices of the electronic devices are compact and has powerful heat dissipating ability.

Referring to FIGS. 7-8, a conventional heat sink comprises a substrate 3 and a plurality of heat dissipating fins 4. A plurality of recesses 31 is defined at a surface of the substrate 3. The substrate 3 defines a groove (not labeled) between every two recesses 31. The recesses 31 have two straight side walls (not labeled). The heat dissipating fins 4 are placed in the recesses 31. A plurality of punching weights 41 punch the grooves so that the walls of the recesses 31 deform and thus the heat dissipating fins 4 are clamped in the recesses 31 tightly. Thereby, the assembly of the heat sink is finished.

Although above the structure can be used, gaps are generated between the fins 4 and the recesses 31. The lower ends of the fins 4 are straight, thus contact areas between the substrate and the fins are small. Heat generated by the CPUs will be transferred to the substrate 3 and thus to the fins 4. The heat can not be quickly transferred to the whole fins since the gaps and the small contact areas between the fins 4 and the recesses 31.

A solution for enhancing the contact areas between the fins and the substrate of the heat sink is needed.

SUMMARY OF THE INVENTION

A heat sink includes a base plate and a plurality of thin-sheet fins. The base plate has a plurality of recesses and protruding ribs formed between every two recesses. The protruding ribs are spaced by the respective recesses with an equal space. Each thin-sheet fin comprises a folded engaging portion and a dissipating portion connecting with the engaging portion. The engaging portion has a first extending portion and a second extending portion parallel to the first extending portion and connecting with the first extending portion. The engaging portions are inserted into the recesses of the base plate and abut against a bottom of the recesses.

Other advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present heat sink can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present heat sink. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an exploded, isometric view of a heat sink in accordance with a first embodiment of the present invention;

FIG. 2 is an assembled view of FIG. 1;

FIG. 3 is a front view of the heat sink of FIG. 2;

FIG. 4 is an enlarged view of a circled portion IV of FIG. 3;

FIG. 5 is a front view of a heat sink in accordance with a second embodiment of the present invention;

FIG. 6 is an enlarged view of a circled portion VI of FIG. 5;

FIG. 7 is a schematic perspective view of a heat sink in accordance with related art after a plurality of punching weights punching grooves of the heat sink; and

FIG. 8 is a schematic perspective view of the heat sink in accordance with related art after the punching weights punching the grooves of the heat sink.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-2, a heat sink (not labeled) of the first embodiment of the present invention is shown. The heat sink comprises a base plate 10 and a plurality of thin-sheet fins 20.

Referring to FIGS. 3-4, the base plate 10 has a flat bottom surface (not labeled) and a top surface (not labeled) opposite to the bottom surface. The base plate 10 defines a plurality of recesses 12 at the top surface thereof and forming elongated protruding ribs 15 spaced by the respective recesses 12 with equal spaces. Each recess 12 has two side faces (not labeled) on the two adjacent protruding ribs 15. Each protruding rib 15 has a tooth configuration and has a dent 18 at a center of a top surface thereof. Each recess 12 consists of a vertical recess (not labeled) perpendicular to a bottom surface of the base plate 10, and an inclined recess (not labeled) below the vertical recess and inclined to the bottom surface of the base plate 10. A projection 19 extends from a side of an upper portion of each protruding rib 15 in a corresponding vertical recess of the recess 12.

Each thin-sheet fin 20 comprises a folded engaging portion 21 and a dissipating portion 28 connecting with the engaging portion 21 and perpendicularity to the bottom surface of the base plate 10. Each engaging portion 21 comprises a curved first extending portion 22 and a curved second extending portion 24 substantially parallel and close to the first extending portion 22. Each first extending portion 22 has an upper vertical portion 225 connecting with the dissipating portion 28, and an inclined portion 226 distant to the dissipating portion 28. The inclined portion 226 connects with the vertical portion 225 in a manner such that there is an obtuse angle between the vertical portion 225 and the inclined portion 226. Each second extending portion 24 has a lower inclined portion 246 connecting with a bottom end of the inclined portion 226 of the first extending portion 22, and an upper vertical portion 245 connecting with the inclined portion 226. The inclined portions 226, 246 are close to each other and the vertical portions 225, 245 are close to each other. The vertical portion 245 of each second extending portion 24 has a free end 247.

In assembly, the engaging portions 21 of the thin-sheet fins 20 are inserted into the recesses 12 of the base plate 10 with the dissipating portions 28 being perpendicularity to the bottom surface of the base plate 10, wherein the vertical portions 225, 245 of the engaging portions 21 are received in the vertical recesses of the recesses 12, and the inclined portion 226, 246 are received in the inclined recesses. The first and second extending portions 22, 24 of the engaging portions 21 attach to the side faces of the recesses 12. The free end 247 of the second extending portion 24 of each thin-sheet fin 20 abuts against the projection 19 of each protruding rib 15 of the base plate 10. A plurality of punching sheets (not show) punch the dents 18 of the protruding ribs 15 of the base plate 10, then the protruding ribs 15 are extruded downwards and produce plastic deformations. The engaging portions 21 of the thin-sheet fins 20 are clamped by side faces of the recesses 12 by plastic deformations of the protruding ribs 15. Thus the protruding ribs 15 are brought into contact with the thin-sheet fins 20. Therefore, the thin-sheet fins 20 are tightly secured to the recesses 12 and the heat sink is formed.

Because the engaging portion 21 of each thin-sheet fin 20 has the folded first and second extending portions 22, 24 respectively contacting with the side faces of recesses 12, the contact areas between the thin-sheet fins 20 and the protruding ribs 15 are so larger that the heat dissipating effect of the heat sink is improved. Furthermore, the free end 247 of the second extending portion 24 of each thin-sheet fin 20 abuts against the projection 19 of each protruding rib 15 of the base plate 20, so that the thin-sheet fin 20 is firmly crimped by the base plate 20. Since each of the protruding rib 15 has a dent 18, each of the punching sheets can punch on the protruding ribs 15 more exactly and easily.

A method of manufacturing the heat sink in the first embodiment comprising the steps of:

a) forming a plurality of recesses 12 at a top surface of a base plate 10 and protruding ribs 15 respectively spaced by the recesses 12 by aluminum extrusion, the protruding ribs 15 has a dent 18 on a center of a top surface thereof;

b) folding an end of each thin-sheet fin 20 to form a vertical dissipating portion 28 and an engaging portion 21 having a first extending portion 22 and a second extending portion 24 parallel and close to the first extending portion 22; curving the first and second extending portion 22, 24 so that the first extending portion 22 has an upper vertical portion 225 and a lower inclined portion 226 connecting with the vertical portion 225, and the second extending portion 24 has a lower inclined portion 246 and an upper vertical portion 245;

c) inserting the engaging portions 21 of the thin-sheet fins 20 in the recesses 12 from a side of the base plate 10 along extending directions of the recesses 12; and

d) punching the dent 18 of the protruding ribs 15 by plastic deformations of protruding ribs 15, the side faces of the recesses 12 crimping the thin-sheet fins 20 in the recesses 12.

FIGS. 5-6 show a heat sink (not labeled) of a second embodiment of the present invention. In this embodiment, the heat sink comprises a base plate 10 a and a plurality of thin-sheet fins 20 a. Each thin-sheet fin 20 a is similar to the thin-sheet fin 20 in the first embodiment, having a folded engaging portion 21 a and a dissipating portion 28 a connecting with the engaging portion 21 a. The engaging portion 21 a has a curved first extending portion 22 a and a curved second extending portion 24 a parallel to the first extending portion 22 a and connecting with a bottom end of the first extending portion 22 a. The first and second extending portion 22 a, 24 a are together continuously curved two times so as to have wavy configurations. In other word, the first and second extending portion 22 a, 24 a respectively have three inclined portions (not labeled) inclined to the dissipating portion 28 a.

The base plate 10 a is similar to the base plate 10 in the first embodiment. The base plate 10 a has a bottom surface and a top surface opposite to the bottom surface. The base plate 10 a defines a plurality of recesses 12 a at the top surface thereof and forming protruding ribs 15 a spaced by the respective recesses 12 a with equal spaces. Each recess 12 a has two side faces (not labeled) on the two adjacent protruding ribs 15 a. The two side faces of each recess 12 a have wavy configurations corresponding to the first and second extending portions 22 a, 24 a of the engaging portion 21 a of each thin-sheet fin 20 a.

A method of manufacturing the heat sink in the second embodiment is similar to that in the first embodiment, only the step b) comprises folding an end of each thin-sheet fin 20 a to form an engaging portion 21 a having a first extending portion 21 a and a second extending portion 22 a parallel to the first extending portion 21 a; curving the first and second extending portion 22 a, 24 a into wavy configurations.

In the second embodiment, the engaging portions 21 a of the thin-sheet fins 20 a having wavy configurations are engaged into the recesses 12 a of the base plate 10 a correspondingly having wavy configurations. Thus the thin-sheet fins 20 a are not easy to be drawn out from the base plate 10 a, and the contact areas between the thin-sheet fins 20 a and the protruding ribs 15 a are so larger that the heat dissipating effect of the heat sink is improved.

It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention. 

1. A heat sink comprising: a base plate having a plurality of recesses and protruding ribs formed between every two adjacent recesses; and a plurality of thin-sheet fins comprising a folded engaging portion and a dissipating portion connecting with the engaging portion, the engaging portion having a first extending portion and a second extending portion parallel to the first extending portion and connecting with the first extending portion, the engaging portion being inserted into the recesses of the base plate and abutting against a bottom of the recesses.
 2. The heat sink as described in claim 1, wherein each second extending portion has a free end, the free end abuts against corresponding protruding rib of the base plate.
 3. The heat sink as described in claim 1, wherein the first and second extending portions of each thin-sheet fin are curved to have portions thereof inclined to the dissipating portion of each thin-sheet fin.
 4. The heat sink as described in claim 1, wherein the first and second extending portions of the engaging portion of each thin-sheet fin are continuously curved and have wavy configurations.
 5. The heat sink as described in claim 1, wherein each recess has a configuration corresponding to that of the engaging portion of each thin-sheet fin.
 6. The heat sink as described in claim 1, wherein the base plate is made of aluminum extrusion.
 7. The heat sink as described in claim 1, wherein each of the protruding ribs has a dent on a center of a top surface thereof.
 8. A method of manufacturing a heat sink, the method comprising the steps of: a) forming a plurality of recesses at a surface of a base plate and protruding ribs respectively spaced by the recesses, each recess having two side faces; b) folding an end of each thin-sheet fin to form an engaging portion having a first extending portion and a second extending portion; c) inserting the engaging portions of the thin-sheet fins in the recesses; and d) punching the protruding ribs by plastic deformations of protruding ribs, the side faces of the recesses crimping the thin-sheet fins in the recesses.
 9. The method as described in claim 8, wherein the base plate is made by aluminum extrusion.
 10. The method as described in claim 8, wherein the second extending portion is parallel and close to the first extending portion.
 11. The method as described in claim 8, wherein the step b) further comprises curving the first and second extending portion so that a lower portion of each engaging portion is inclined to the other portion of each thin-sheet fin.
 12. The method as described in claim 8, wherein the step b) further comprises curving the first and second extending portion into wavy configurations.
 13. The method as described in claim 8, wherein each of the protruding ribs has a dent on a center of a top surface thereof.
 14. The method as described in claim 8, wherein the thin-sheet fins are inserted from a side of the base plate along extending directions of the recesses in the step c).
 15. A heat sink comprising: a base plate defining a plurality of first recesses and a plurality of second recesses communicating with the first recesses, each first recess inclined relative to each second recess; and a plurality of fins inserted into the first and second recesses, each fin comprising a folded first portion received in corresponding first recess and a second portion vertically extending from the first portion and partially received in corresponding second recess; wherein a step portion is formed at a joint of the each first and second recess, and a free end of the first portion abuts against the step portion.
 16. The heat sink as described in claim 15, wherein the first portion of each fin is inclined relative to the second portion.
 17. The heat sink as described in claim 15, wherein the first portion of each fin has a substantially U-shaped configuration.
 18. The heat sink as described in claim 17, wherein a bottom of the first portion abuts against a bottom of the first recess of the base plate. 